AVS 50th International Symposium
    Applied Surface Science Wednesday Sessions
       Session AS-WeP

Paper AS-WeP1
A Simple Method Identifying the Influence of Photoperturbation Effect on Ultrashallow Junction Images Observed by Scanning Capacitance Microscope

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: M.-N. Chang, National Nano Device Laboratories, Taiwan, R.O.C.
Authors: M.-N. Chang, National Nano Device Laboratories, Taiwan, R.O.C.
W.-W. Wan, National Tsing Hua University, Taiwan, R.O.C.
J.-H. Lai, National Tsing Hua University, Taiwan, R.O.C.
C.-Y. Chen, National Nano Device Laboratories, Taiwan, R.O.C.
F.-M. Pan, National Nano Device Laboratories, Taiwan, R.O.C.
J.-H. Liang, National Tsing Hua University, Taiwan, R.O.C.
Correspondent: Click to Email
Scanning capacitance microscopy (SCM) with high sensitivity and high spatial resolution has attracted much interest in profiling two-dimensional carrier distribution and investigating ultrashallow junctions. Atomic force microscope (AFM), equipped with a SCM system, is a typical setup that synchronously provides SCM images and the corresponding topographic images for cross-sectional characterization. In this work, we have provided a simple method to investigate the influence of photoperturbation effect induced by AFM laser beam on ultrashallow junction images observed by SCM. The samples were ultrashallow p@super +@ junctions formed by BF@sub 2@@super +@ implantation at low energies. RTA processes were performed at 1050 °C for different anneal times from 5 to 30 seconds in N@sub 2@ ambient. The width and pitch of the designed grating pattern are 0.8 and 2 @micro@m, respectively. It is revealed that the photoperturbation effect induced by AFM laser beam leads to SCM image broadening and junction region narrowing. In other words, the photoperturbation effect not only significantly affects the dC/dV signals but also deteriorates the accuracy of junction characterization, in particular for ultrashallow junctions. The experimental results will be shown and discussed. The section analysis also reveals that there are distorted differential capacitance (dC/dV) profiles in the photoperturbed SCM images. Comparing dC/dV profiles of various photoperturbed SCM images, one can identify the area not affected by AFM laser beam. This simple method allows us to identify the influence of the photoperturbation effect on the pattern region. According to this study, the pattern edge region is more sensitive to the photoperturbation effect than the pattern central region.